Low soft error rates

Sample quantities of Enhanced Memory Systems’ 72Mb No Bus Latency Burst Enhanced SRAM are now being delivered to customers.

Samples and pre-production quantities of Enhanced Memory Systems’ 72Mb No Bus Latency (NoBL) Burst Enhanced SRAM (ESRAM) are now being delivered to customers.

The new 72Mb NoBL ESRAM, which uses Enhanced’s proprietary one-transistor Enhanced SRAM (ESRAM) architecture, is claimed to be the highest-density SRAM replacement product available.

Enhanced Memory Systems also disclosed that its one-transistor ESRAM, which uses an advanced trench DRAM process, provides a significant improvement in soft-error performance over both high-density SRAM and embedded SRAMs built on logic-based CMOS processes.

‘Testing of the trench capacitor process shows very low soft-error rates compared to current high-density SRAM and logic-based one-transistor SRAM products,’ said Dave Fisch, Enhanced business vice president.

System failures due to soft errors have become a growing concern in the SRAM industry. Soft errors occur when an alpha particle emitted by materials in semiconductor packaging or naturally occurring neutrons from cosmic rays disturb a memory storage cell, causing a loss of stored data. As six-transistor SRAMs are scaled to higher densities, they become increasingly susceptible to soft errors. The NoBL Burst ESRAM provides a reduction in soft errors due to its high-capacitance trench capacitor and one-transistor SRAM architecture.

The 72Mb NoBL Burst SRAM products are organized 2 Mb x 36, operate at up to 166 MHz clock speed and deliver 100-percent bus bandwidth during four-word read-write transactions. The products are available with 2.5V or 3.3V power supply options and 100-pin TQFP and 119-pin PBGA packaging options.

The 72Mb NoBL is pin-compatible with existing 18Mb NoBL or ZBT SRAM products to allow multiple SRAMs to be replaced with a single lower-cost, lower-power ESRAM. Samples are priced at $80 each in small quantities and are available immediately. The products are pin-function and timing-compatible with NoBL SRAMs, making them ideal upgrades in network systems that require larger SRAM buffer memories.

Enhanced Memory Systems is a subsidiary of Ramtron International.

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